JP2004532739A - Rotary tool for serial drilling of shaped articles - Google Patents

Abstract

There are upper and lower rotating cutting tools, the upper tool consisting of a stack of basic circular tools (11) and dividers (12). These are mounted and locked on a shaft (6). The lower tool also consists of a stack of lateral cutters (22).

Description

【図面の簡単な説明】
【００６３】
【図１】本発明による回転道具システムの上面図を示す。
【図２】図１による第一対の回転道具に属する二つの道具要素を示す。
【図３】この発明による第一対の回転道具の立面図を示す。
【図４】図３に示された上部回転道具の歯の二つの特別の実施例を示す。
【図５】この発明の好適実施例による第一対の道具により作られた切れ目の詳細を示す。
【図６】図１の第二対の対応する回転道具に属する両方の道具要素の詳細図を示す。
【図７】この発明による第二対の回転道具の立面図を示す。
【図８】この発明による金属シートの切抜きのための最適配置図を示す。
【図９】図８に示された切抜きと同様の切抜きを規定することを可能とするパラメーターを示す。
【図１０】この発明による切抜き図の実例を示す。
【図１１】縦方向及び横断方向のそれぞれ交互にこの発明の第二好適実施例による第一対の道具により作られた切れ目の詳細を示す。
【図１２】図１１の切れ目に対応する第二対の道具の単純な折り曲げ道具の歯の詳細を示す。[0001]
FIELD OF THE INVENTION The present invention relates to a new method for combining cutting and shaping industrial operations, preferably in series.
[0002]
The invention also relates to a rotating tool enabling the method to be performed.
[0003]
State of the art The combination of cutting and shaping operations is known in many industrial applications. These cutouts may be fewer or, in contrast, the density of the cutouts may be very high. Such is the case, for example, for acoustic shaped products or shaped products intended to act as cable conduits.
[0004]
One technique for producing sound-absorbing bulkheads for acoustics is based on the use of a shaped metal surface having a surface with multiple holes. Current methods generally consist of using either a porous shaped product with round holes of small diameter or otherwise a pierced shaped product. Stab holes are partial cutouts that leave cutout debris attached to the metal sheet, and these cutouts are generally rectangular. The shaped articles described above are characterized by very dense cutouts of holes on the order of thousands per square meter.
[0005]
Shaping is among the most used technologies that make cable conduits manufacturable. In this case, the cutting and shaping operations must be combined. The number of cutouts is lower, but still very high, for acoustic shaped articles.
[0006]
Other products, such as uprights for metal shelves, are generally made from shaped products with cutouts. In this last example, the number of cutouts in each case is much smaller.
[0007]
Various methods are used to obtain these shaped articles with more or less cutouts. In fact, the two main groups of methods must be distinguished depending on whether the cutout is made by a press or by a rotating tool.
[0008]
The cut made by the press can be made before the shaping operation, off the shaping line, or by a press installed in the shaping line or even after the shaping operation.
[0009]
When cutouts are made before and off the shaping line, there are many additional processing steps, with significant additional costs. When the press is placed in the shaping line, the cutting operation greatly reduces the shaping speed. Finally, post-shaping cutout creation places restrictions on the placement of cutouts on the shaped product. Because of the access restrictions imposed by the cutting tool, it also has a negative effect on productivity.
[0010]
Rotating tools provide an interesting alternative to the use of a press in the sense that they can be operated at speeds consistent with the speed of the shaping line.
[0011]
Tools of this type include, for example, patents (patent applications) GB-A-1044313, GB-A-1123536, US-A-1581236, US-A-1333704, US-A-3828636, US-A-3205744, US-A No. 3,709,077, US Pat. No. 3,438,835, US Pat. No. 3,274,873, US Pat. No. 3,066,542 and US Pat. No. 5,040,397. The systems described in these various documents do not provide a suitable solution to the problem considered here. They are either intended only for the cutting operation and not for hole formation, or they are very complex and expensive to perform when many holes have to be made. In particular, their problem is the emission of very large amounts of debris resulting from pore formation.
[0012]
Thus, the alternative implemented in this case is a piercing hole, which consists of making a partial cut-out leaving debris adhered to the metal sheet, which eliminates the problem of its evacuation. This operation can be performed by a rotating tool, but it has other disadvantages. The lower knife is a disc, the fine cutting is achieved only in the direction parallel to the movement of the metal sheet, the vertical side is rather torn, which may reduce the resistance to rust. Furthermore, debris remaining on the metal sheet hinders the production of piercing holes in the area of contact with the shaping rollers, which significantly reduces the relative surface of the shaped product from which the piercing holes are actually made. In addition, due to the rotating tool technology, the angle of the debris with respect to the plane of the metal sheet is closer to 45 ° than 90 °, which significantly reduces the visible aperture. Acoustic shaping products made by piercing techniques therefore provide significantly worse performance than those made by drilling.
[0013]
U.S. Pat. No. 4,766,707 describes a machine that includes a first pair of rotating drums for drilling followed by a second pair of rotating drums for cutting metal strip. According to the proposed equipment, this machine follows a forming or folding machine to create clips intended for roofing panels. The first pair of tools make a conical stamp or hole which will later serve to receive the fastening means, such as a nail. The second pair of tools creates a transverse groove on each longitudinal edge of the strip, and the two adjacent portions of the strip are now only loosely connected in the middle to favor subsequent easy separation of the clip . The speed of both types of operation is significantly different.
[0014]
U.S. Pat. No. 1,931,468 describes a similar arrangement, in which the movements of pairs of rollers are coordinated by a gear-driven system. Drilling in one or two operations is achieved by a pair of rotating tools, one of which has a groove for chip removal.
[0015]
Object of the invention The object of the present invention is to provide a solution which makes it possible to overcome the disadvantages of the prior art.
[0016]
In particular, the invention makes it possible to either cut out a large number of small sized holes on the shaping line or to make a stab hole with improved geometry without adversely affecting the shaping speed The purpose is to propose a rotating tool technology.
[0017]
Main characteristic elements of the invention The present invention relates to an apparatus comprising a rotary cutting tool for combining a cutting and shaping operation on a metal sheet, wherein the density of the cutting is preferably very high, said cutting operation being It is preferably integrated into the automated shaping line, which is used to obtain a first pair of rotary cutting tools to make a first set of cuts and a final closed loop cut or stab hole by dropping chips. And a second pair of rotary cutting tools for completing and finishing the first set of cuts by forming or folding two sets of cuts.
[0018]
According to a first preferred embodiment of the invention, the final cutout is essentially rectangular and the first pair of rotating tools make a cut transverse to the direction of movement of the metal sheet to make the cut, The pair of rotating tools make a longitudinal cut in the direction of movement of the metal sheet. It should be noted that the roles of the tools in both pairs may be reversed (the first cut is longitudinal and then transverse).
[0019]
According to a second preferred embodiment of the invention, the final cutout is essentially rectangular and of the piercing type, wherein the first pair of tools makes a cut on three adjacent sides of the rectangle, Two pairs of tools make a fold about the axis formed by the fourth side of the rectangle.
[0020]
Preferably said rotating tool is mounted on an axis supported by bearings, said axis being perpendicular to the direction of movement of the metal sheet.
[0021]
Advantageously, the direction of rotation of the upper and lower tools is such that at the point of contact with the metal sheet, the tangential speed of said tool is in the same direction and essentially the same as the speed at which the metal sheet passes.
[0022]
As a special advantage, said device comprises means for ensuring relative positioning depending on the circumference of the teeth of the upper and lower tools of said pair of circular tools, said means preferably being axially synchronized. It is a gearbox that absorbs play for
[0023]
According to a special embodiment of the device of the invention, the first pair of tools comprises an upper tool comprising an alternating row of simple circular knives and spacers, and an alternating row of elements acting as simple circular knives and side knives. Including lower tools. In addition, the second pair of tools includes an upper tool and a lower tool, each including an alternating row of simple circular knives and spacers.
[0024]
Advantageously, each simple upper circular knife includes a plurality of teeth around its periphery, the arc of which is made by a first pair of tools associated with the same final cut independently for each set of cuts. It has a length equal to the distance between two cuts. This simple circular knife, together with the spacers of the second pair of tools, has an essentially equal width independently for each set of cuts.
[0025]
The device according to the invention advantageously comprises means for assisting in the removal of the swarf, preferably a comb, the teeth of which fit between the simple circular knives of the second pair of tools.
[0026]
According to the invention, the upper tool of the second pair of tools can be provided with round or smooth teeth at the level of the fold line and has a set number corresponding to the fold.
[0027]
Another aspect of the invention relates to a method for a combined perforated cutting and shaping operation of a metal sheet, wherein the density of the cuts is preferably very high, said cutting operation preferably being performed in an automated shaping line. Combined into the following continuous stages:
The first pair of rotary cutting tools makes a first set of cuts transverse to the direction of movement of the metal sheet;
The second pair of rotary cutting tools makes a second set of cuts in the longitudinal direction with respect to the direction of movement of the metal sheet, the result of the combination of the two operations being a set of closed loop cuts, preferably rectangular;
The chippings are ejected by the movement of the tool, preferably by a comb incorporated in the second pair of tools and / or transversely by a transport belt;
Is characterized by:
[0028]
The present invention also relates to a method of combining a piercing and shaping operation on a metal sheet, said piercing operation preferably being integrated into an automated shaping line and comprising the following successive steps:
The first pair of rotary cutting tools make a first set of U-shaped cuts forming a rectangle;
A second pair of rotary cutting tools make a fold, the fold axis of which is intended to be on the remaining side to form a set of rectangular cutouts of a piercing type;
Is characterized by:
[0029]
As a special advantage, the method of the invention can combine, on the same machine, a piercing and piercing operation distributed along a metal sheet strip parallel to the direction of movement of the metal sheet, said piercing hole being Made in areas that do not come into contact with the shaping tool.
[0030]
Advantageously, the perforated or pierced rectangular cutout is displaced and the displacement between two adjacent cutouts is equal to the longitudinal pitch (Plg) divided by the displacement parameter X (X is not zero).
[0031]
In practical use, the device of the present invention is used to make sound-absorbing bulkheads for acoustics, to make cable conduits, or even to make metal shelves.
[0032]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a top view of a rotating tool system according to the present invention.
[0033]
FIG. 2 shows two tool elements belonging to the first pair of rotary tools according to FIG.
[0034]
FIG. 3 shows an elevation view of a first pair of rotating tools according to the present invention.
[0035]
FIG. 4 shows two special embodiments of the teeth of the upper rotating tool shown in FIG.
[0036]
FIG. 5 shows details of the cut made by the first pair of tools according to a preferred embodiment of the present invention.
[0037]
FIG. 6 shows a detailed view of both tool elements belonging to the second pair of corresponding rotary tools of FIG.
[0038]
FIG. 7 shows an elevation view of a second pair of rotating tools according to the present invention.
[0039]
FIG. 8 shows an optimal layout for cutting out a metal sheet according to the invention.
[0040]
FIG. 9 shows the parameters that make it possible to define a cutout similar to the cutout shown in FIG.
[0041]
FIG. 10 shows an example of a cutout diagram according to the present invention.
[0042]
FIG. 11 shows details of a cut made by a first pair of tools according to a second preferred embodiment of the present invention, alternately in the longitudinal and transverse directions, respectively.
[0043]
FIG. 12 shows the details of the teeth of the simple folding tool of the second pair of tools corresponding to the cuts in FIG.
[0044]
The operation as this detailed description <br/> present invention relates to ensure folding with good quality cut in the case of good quality and easy discharge or puncture in waste clippings when clippings The purpose is to obtain either a rectangular cutout or a stab hole by dividing it into two stages.
[0045]
The basic principle illustrated in FIG. 1 consists in using two successive pairs of rotating tools. In the case of hole cutting, this principle allows the cutting operation to be divided into two stages. On the one hand, the first pair of rotating knives make a cut transverse to the direction of movement of the metal sheet. On the other hand, the second pair makes longitudinal cuts, ensuring easy discharge of debris. In the case of a piercing-type cutout, the first pair of knives make a cut, for example, on three sides. The second pair then folds the breaks, which makes it possible to obtain a significantly improved visible aperture compared to the state of the art. Furthermore, in the closely related prior art U.S. Pat. No. 4,766,707, continuous operations (embossing or drilling, shearing) performed by rotating tools are performed in different areas and are used for completely different purposes. ing.
[0046]
FIG. 1 shows a top view of this system. A first pair of rotating tools, including tools 1 and 2 mounted on shafts 6 and 6 ', respectively, make partial cuts in the metal sheet without discharging debris. This cut is completed by a second pair of tools, including tools 3 and 4 mounted on shafts 6 "and 6"', respectively. These axes are supported by bearings mounted in a head similar to a shaping head (not shown). The direction of rotation of each tool is indicated by (B, B ', B ", B""). The metal sheet moves in the direction A shown and is equal to the peripheral speed shared by the tools 1, 2, 3 and 4.
[0047]
Description of some preferred embodiments of the invention Figures 2 and 3 show preferred embodiments of the rotating tools 1 and 2. In particular, FIG. 2 shows the upper and lower 21 circular tool elements, which make a cut 7 perpendicular to the direction of movement of the metal sheet 5 (see FIG. 5). As shown in FIG. 3, the upper tool 1 includes a stack of simple circular tools 11 and spacers 12. These tool elements are mounted on a shaft 6, positioned and fixed on the shaft in a rotational direction by elements such as pins. These elements are also fixed axially to ensure accurate positioning. The lower tool 2 likewise comprises a stack of elements 21 facing the element 11 and separated by an element 22 which serves as a side knife when cutting the cut 7. The elements 21 and 22 are fixed in the rotational direction and are axially positioned as in the case of the tool 1. Elements 11, 21 and 22 are preferably made from heat treated tool steel, as is the case with standard cutting tools.
[0048]
This method of construction of a rotating tool is to enable economical manufacture of the tool, since elements such as 11 or 21 can be made by wire cutting a stack of disks made from heat treated tool steel. Is particularly advantageous.
[0049]
Axial positioning of the tools 1 and 2 is ensured by stops mounted on the shaft at the level of bearings provided in the support head. The relative radial positioning of the teeth of the circular tools 11 and 21 is ensured by at least one gearbox which synchronizes the axes 6 and 6 '. These are gears which preferably absorb play to ensure a precise positioning which is consistent for each set of cuts. At least one of the shafts 6 or 6 'is motor-driven so as to ensure a rotational peripheral speed of the tool equal to the moving speed A of the metal sheet.
[0050]
FIG. 4 shows two embodiments of the teeth 111 or 111 ′ of the circular tool 11.
[0051]
After passing through the first pair of rotating tools, the metal sheet has a cut 7 as shown in FIG.
[0052]
6 and 7 show simple knives 31 and 41 for performing the second cutting operation. The circular knife 31 has teeth 311 around it, which arc has a length equal to the distance between two consecutive cuts 7 independently for each set of cuts. The complete upper circular tool 3 comprises a stack of simple knives 31 separated by spacers 32. The axial and circumferential positioning of the knife 31 is ensured in a manner similar to that of the tools 1 and 2. In addition, the shaft 6 '' is tuned with respect to the shaft 6 to ensure the correct positioning of the cut 7 with respect to the knife 31. This tuning is achieved, for example, by a gear system.
[0053]
The tool 4 includes a stack of simple cutting disks 41 and spacers 42 (FIG. 7). Their axial positioning is ensured like tools 1 and 2, and the relative positioning of tools 3 and 4 must be guaranteed only in the axial direction. The tool elements 11, 21 and 31 and the spacer 42 have an equal width independently for each set of cuts.
[0054]
Cut-out debris is very easily ejected between the discs 41, and a comb, possibly with teeth that fit between the discs 41, can be provided to ensure the evacuation of debris stuck between the cutting discs 41. The debris is then discharged transversely, for example by means of a transport belt.
[0055]
FIG. 8 schematically shows the optimal arrangement of the cutouts. Indeed, a subtle step of the method is to apply an appropriate amount of cutting force, especially when cutting the cuts by tools 1 and 2. Therefore, to reduce this force, it may be beneficial to displace the cutout as shown in FIG.
[0056]
The parameters to be considered are shown in FIG. 9, which are: transverse pitch Ptr, longitudinal pitch Plg, transverse cut DecTr and longitudinal cut DecLg. For example, the cutout ratio, which is a parameter that determines the acoustic characteristics of the panel, is the ratio between the cutout surface area (DecTr × DecLg) and the pitch surface area (Plg × Ptr). A sufficiently high value is chosen for the parameter X which determines the displacement so as to reduce the axial force. In fact, the higher the value of the parameter X, the fewer cuts are made at the same time, especially if X is not an integer.
[0057]
Another important parameter is the uncut longitudinal length, the ratio between Plg-DecLg and the displacement pitch, Plg / X. If this ratio is an integer, some of the first cutouts of the rectangular hole will coincide with a second cutout displaced by a number of rows equal to said ratio. In this case, the number of cuts made at the same time is relatively high, which imposes a relatively high bending load on the axis, but the cuts made in pairs compensate for the radial forces on the knife and make it Reduce the torque applied to the If the cutout parameters are chosen such that this ratio (Plg-DecLg) / (Plg / X) is not an integer, the number of cutouts made at the same time is reduced, which reduces the bending force but reduces the torque applied to the shaft. increase.
[0058]
Table 1 shows a suitable choice of parameters corresponding to non-integer ratios, and FIG. 10 shows a simple example of a cutout pattern.
[0059]
The technique of the present invention also optimizes piercing, i.e., no material ejection, cutout.
[0060]
The technology of this tool is the same in principle. A U-shaped cut is made in the first pair of tools 1 and 2 as shown at 7 '(longitudinal) or 7''(transverse) in FIG. The teeth of the type 111 of the simple tool 11 are thus adapted. A fold that is no longer cut as described above is made at 8 by the second pair of tools. Thus, the teeth 311 of the simple tool 31 are, of course: rounded at the level of the fold edges and adapted to have the number of sets corresponding to the fold. FIG. 12 shows a typical view of this type of puncture for the longitudinal and transverse directions.
[0061]
For these various uses, the tool diameter will be specified taking into account the material resistance that sets the dimensions of the shaft, and also by the contact conditions of the circular tool with the metal sheet. Accordingly, the radius of tools 1 and 2 will preferably be equal to or greater than 100 times the thickness of the metal sheet. In the case of a piercing hole, different radii can be chosen for the tools 3 and 4, and the tool 4 can have a considerably larger radius than the tool 3, for example to ensure good support for the metal sheet during a folding operation. .
[0062]
In one particular embodiment, the cutting and piercing operations can be incorporated into a single machine along a belt parallel to the direction of movement of the metal sheet, with the piercing in areas not in contact with the shaping tool. Is located.
[Table 1]

[Brief description of the drawings]
[0063]
FIG. 1 shows a top view of a rotating tool system according to the present invention.
FIG. 2 shows two tool elements belonging to a first pair of rotary tools according to FIG. 1;
FIG. 3 shows an elevation view of a first pair of rotating tools according to the present invention.
FIG. 4 shows two special embodiments of the teeth of the upper rotating tool shown in FIG.
FIG. 5 shows details of a cut made by a first pair of tools according to a preferred embodiment of the present invention.
FIG. 6 shows a detailed view of both tool elements belonging to the second pair of corresponding rotating tools of FIG. 1;
FIG. 7 shows an elevation view of a second pair of rotating tools according to the present invention.
FIG. 8 shows an optimum layout for cutting out a metal sheet according to the invention.
FIG. 9 shows parameters that allow defining a cutout similar to the cutout shown in FIG.
FIG. 10 shows an example of a cut-out view according to the present invention.
FIG. 11 shows details of a cut made by a first pair of tools according to a second preferred embodiment of the present invention, alternately in longitudinal and transverse directions respectively.
FIG. 12 shows the details of the teeth of a simple folding tool of the second pair of tools corresponding to the cuts in FIG. 11;

Claims (20)

An apparatus comprising a rotary cutting tool for combining cutting and shaping operations of a metal sheet, preferably having a very high cutout density, wherein said cutting operation is preferably integrated into an automated shaping line. , A first pair of rotary cutting tools (1,2) for making a first set of cuts (7,7 ', 7' ') and a second for obtaining a final closed loop cut or pierced hole respectively by dropping of cut chips. An apparatus characterized in that it comprises a second pair of rotary cutting tools (3, 4) for completing and finishing the first set of cuts by a set of cuts or folds (8). The final cutout is essentially rectangular, the first pair of rotating tools (1,2) making a cut transverse to the direction of movement (A) of the metal sheet to make a cut (7); 2. The device according to claim 1, wherein the two pairs of rotating tools (3, 4) make longitudinal cuts with respect to the direction of movement (A) of the metal sheet. The final cutout is essentially rectangular and of the pierced hole type, wherein said first pair of tools (1,2) has cuts (7 ', 7' ') on three adjacent sides of said rectangle. Device according to claim 1, characterized in that the second pair of tools (3, 4) makes a fold (8) about an axis formed by the fourth side of the rectangle. The rotary tools (1, 2, 3, 4) are mounted on shafts (6, 6 ', 6 ", 6"') supported by bearings, and the shafts are moved in the direction of movement (A) of the metal sheet. 4. Apparatus according to claim 1, characterized in that it is perpendicular to. The rotational direction of the upper tool (1,3) and the lower tool (2,4) is such that the tangential speed of the tool at the point of contact with the metal sheet is in the same direction and essentially the same magnitude as the speed at which the metal sheet passes. Apparatus according to any of claims 1 to 4, characterized in that it is of the type described above. Means for ensuring relative positioning depending on the circumference of the teeth (111, 111 ', 211, 211') of the upper tool (1) and the lower tool (2) of the pair of circular tools. Apparatus according to any one of the preceding claims, characterized in that said means are gearboxes, which preferably absorb play to synchronize the axes (6, 6 '). A first pair of tools (1,2) acts as upper tool (1) including alternating rows of simple circular knives (11) and spacers (12), as well as simple circular knives (21) and side knives. Apparatus according to any one of the preceding claims, comprising a lower tool (2) comprising alternating rows of elements (22). A second pair of tools (3,4) includes an upper tool (3) and a lower tool (4), each of which includes an alternating row of simple circular knives (31,41) and spacers (32,42). Apparatus according to any one of claims 1 to 6, characterized in that: Each upper simple circular knife (31) includes teeth (311) around its circumference, the arc of which is independently associated with the same final cut and the first pair of tools (1,2) for each set of cuts. 9. Device according to claim 8, characterized in that it has a length equal to the distance between the two cuts (7) made by the method. 10. A method according to claim 7, wherein the simple circular knives (11, 21, 31) and the spacers (42) of the second pair of tools have the same width independently for each set of cuts. An apparatus according to any one of the preceding claims. Device according to claim 8, characterized in that it comprises means, preferably a comb, for assisting in the removal of cuttings, the teeth of which are fitted between the simple circular knives (41) of the second pair of tools. . The tool (3) of a second pair of tools is rounded or smooth at the level of the fold line and is provided with teeth (311) having a set that matches the fold. An apparatus according to claim 3. The final cut is essentially rectangular, the first pair of rotating tools (1,2) making a longitudinal cut in the direction of movement (A) of the metal sheet, and the second pair of rotating tools (3,3). 4. The device according to claim 1, wherein 4) cuts transversely with respect to the direction of movement (A) of the metal sheet. Claims 1. A method for combining a perforated form of a metal sheet with a shaping operation, wherein the density of the cuts is preferably very high, said cutting operations being preferably integrated in an automated shaping line. 2. In a method for using the device according to 2, the following successive steps:
A first pair of rotary cutting tools (1, 2) make a first set of transverse cuts (7) with respect to the direction of movement (A) of the metal sheet;
The second pair of rotary cutting tools (3, 4) makes a second set of longitudinal cuts with respect to the direction of movement (A) of the metal sheet, the combined result of both operations being a set of closed loop cuts, preferably rectangular. ;
The chippings are ejected by the movement of the tool, preferably by a comb incorporated in the second pair of tools and / or transversely by a transport belt;
The method characterized by the above. A method for combining piercing and shaping operations in a metal sheet, said piercing operation preferably being integrated in an automated shaping line, for use with an apparatus according to claim 3. In the method, the following successive steps:
A first pair of rotary cutting tools (1, 2) make a first set of U-shaped cuts (7 ', 7 ") forming a rectangle;
The second pair of rotary cutting tools (3, 4) makes a fold (8), the fold axis of which is intended to be on the remaining side for forming a set of punctured rectangular cutouts; There;
The method characterized by the above. Incorporating cutout and piercing operations distributed along a strip of metal sheet parallel to the direction of movement of the metal sheet on a single machine, such that the piercing holes are made in areas that do not contact the shaping tool. An apparatus according to claim 14 or claim 15, characterized in that: The rectangular perforated or pierced cutout is displaced and the displacement between two adjacent cutouts is equal to the longitudinal pitch (Plg) divided by a non-zero displacement parameter X. Apparatus according to claim 14 or 15. Use of the device according to any one of claims 1 to 13 for making a sound-absorbing bulkhead for acoustics. Use of the device according to any one of claims 1 to 13 for making cable conduits. Use of the device according to any one of claims 1 to 13 for making metal shelves.

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